Optics: measuring and testing – By polarized light examination – With light attenuation
Reexamination Certificate
1999-03-22
2001-06-26
Pham, Hoa Q. (Department: 2877)
Optics: measuring and testing
By polarized light examination
With light attenuation
Reexamination Certificate
active
06252659
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a three-dimensional measurement apparatus, and more particularly to a so-called active type three-dimensional measurement apparatus that captures three-dimensional data by projecting a reference beam on a target object and receiving its reflected light.
BACKGROUND OF THE INVENTION
In the prior art, so-called active type three-dimensional measurement apparatuses have been known that capture three-dimensional data by projecting a reference beam on a target object and receiving its reflected light. Among these types of devices, an apparatus that can generate both a range image (the image used to measure distance and to calculate the three-dimensional shape of the target object) and a color image (the image used to display the target object) is known, as disclosed for example, in Japanese Patent Unexamined Publication No. 9-145319.
FIG. 19
is a block diagram showing the configuration of such an active type three-dimensional measurement apparatus. Referring to the figure, a beam splitter (beam-splitting prism)
52
is constructed with a color separation film (dichroic mirror)
521
, two prisms
522
and
523
sandwiching the color separation film
521
, a range image capturing CCD sensor
53
provided on the emergent face of the prism
522
, and a color image capturing CCD sensor
54
provided on the emergent surface of the prism
523
.
A target object is scanned by a reference beam emitted from a semiconductor laser, and the light reflected by the target object enters a light receiving lens
51
a
. The light that enters the light receiving lens
5
la passes through the prism
522
and reaches the color separation film
521
. Light U
0
lying in the oscillation wavelength region of the semiconductor laser is reflected by the color separation film
521
and directed toward the range image capturing CCD sensor
53
. On the other hand, light C
0
transmitted through the color separation film
521
passes through the prism
523
and enters the color image capturing CCD sensor
54
.
The range image capturing CCD sensor
53
is driven by a range image capturing CCD driver
204
. The color image capturing CCD sensor
54
is driven by a color image capturing CCD driver
203
. The output of the range image capturing CCD sensor
53
is processed by an A/D converter (an output processing circuit)
202
, and then stored in a range image frame memory
206
. The output of the color image capturing CCD sensor
54
is processed by an A/D converter (an output processing circuit)
201
, and then stored in a color image frame memory
205
.
The prior art active type three-dimensional measurement apparatus described above has exhibited the following limitations, due to the use of the two CCD sensors
53
and
54
.
(1) The mounting positions of the two CCD sensors must be adjusted very precisely so as to eliminate misregistration between the range image and the color image.
(2) Since near infrared light is primarily used for the reference beam, it is necessary to produce a prism that can separate incident light into near infrared light for the range image and visible light for the color image.
(3) The quality of the color image is dependent on the spectral characteristics of the prism that is used.
The present invention has been devised to address the above-listed limitations, and one object of the invention is to solve the problems associated with the use of two sensors in a three-dimensional measurement apparatus.
SUMMARY OF THE INVENTION
To achieve the above object, according to one aspect of the present invention, a three-dimensional measurement apparatus comprises projecting means for projecting a reference beam toward a target object to be measured, light receiving means for receiving light reflected from the target object, and calculating means for calculating a three-dimensional shape of the target object from the received reflected light. In this apparatus, an image for calculating the three-dimensional shape of the target object and an image for displaying the target object are captured by the same sensor.
According to the present invention, since the image for calculating the three-dimensional shape of the target object and the image for displaying the target object are both captured by the same sensor, there is no need to adjust the mounting positions of two sensors, which was the case with the prior art. Furthermore, there is no need to produce a prism capable of separating incident light into near infrared light and visible light, and therefore, the quality of the color image can be improved.
REFERENCES:
patent: 4072405 (1978-02-01), Ozeki
patent: 5129010 (1992-07-01), Higuchi et al.
patent: 5177556 (1993-01-01), Rioux
patent: 5608529 (1997-03-01), Hori
patent: 5668631 (1997-09-01), Norita et al.
patent: 6141105 (2000-10-01), Yahashi et al.
patent: 7-174536 (1995-07-01), None
patent: 09145319A (1997-06-01), None
Ide Eiiehi
Kamon Koichi
Norita Toshio
Tanabe Hideki
Uchino Hiroshi
Burns Doane , Swecker, Mathis LLP
Minolta Co. , Ltd.
Pham Hoa Q.
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